In the 1950’s Stanford University’s Electronics Research Laboratory (ERL) continued to develop innovative microwave tubes for the U.S. military. This next product, the Traveling Wave Tube, would have a major impact on electronic intelligence. Stanford’s Dean of Engineering, Fred Terman, encouraged scientists and engineers to set up companies to build these microwave tubes for the military. Funded by military contracts, these 1950’s microwave tube startups would help build Silicon Valley’s entrepreneurial culture and environment.

Why Electronics Intelligence?
Starting in 1946 Electronic Intelligence aircraft (ELINT) had been probing and overflying the Soviet Union to understand their air defense system. During the 1950’s, the U.S. Air Force Strategic Air Command, U.S. Navy and the CIA were the primary collectors of tactical and operational ELINT on the Soviet PVO Strany Air Defense system. (The NSA owned COMINT collection.) They flew an alphabet soup of Air Force and Navy planes (Navy PB4Y-2’s, P2V’s, P4M’s and EA-3’s, Air Force B-17s, EC-47’s, RB-29s, RB-50’s, and the ultimate ELINT collector of the 1950’s – the RB-47H.) Common to all these planes (generically called Ferrets) is that they were loaded with ELINT receivers, manned by crews called Crows.

The Strategic Air Command needed this intelligence to understand the Soviet air defense system (early warning radars, Soviet fighter plane radar, Ground Control Intercept radar, Anti-Aircraft gun radar, and radars guiding Soviet Surface to Air Missiles.) We needed this data to build radar jammers that could make the Soviet air defense radars ineffective so our bombers with their nuclear payloads could reach their targets. The information we collected would be passed on to defense contractors who would build the jammers to confuse the Soviet air defense radars.

ELINT TaskingThe ELINT program sought answers to operational questions like: What was the Radar Order of Battlea penetrating bomber would face? Were there holes in their radar coverage our bombers could sneak through? What was the best altitude to avoid the Soviet defenses? ELINT operators on each flight were tasked to gather basic data about the characteristics of the radar: is this a new type of radar or an existing one? What is its frequency, power, pulse repetition interval, rotation rate, scan rate, polarization, carrier modulation characteristics, etc. Then they would use direction finding equipment on their aircraft to locate its position.

ELINT Receivers
Early ELINT receivers were not much different then the radios you had at home – someone had to manually turn a dial to tune them to the correct frequency. By the 1950’s these receivers could automatically “sweep” a frequency band, but this action was mechanical and slow. That was fine if the Soviet radar was operating continuously, but if it was just a brief radar transmission or burst communication (which Soviet submarines used), we would probably miss hearing it. (The Soviets kept their radars turned off to stop us from recording their signals. So at times multiple ELINT planes would fly on a mission – one to run at the Soviet border appearing to attack, the other to pick up the signals from the air defense network as it responded to the intrusion. Keep in mind that 32 of these planes were shot down in the Cold War.)

The ultimate dream of ELINT equipment designers was a “high-probability of intercept” receiver, one that would pick up a signal that came up on any frequency and capture even a single pulse, however brief.

This was a two-pronged challenge: the U.S. needed receivers that could tune much faster than any of the manual methods that existed, and it needed receivers that could tune a much broader range of frequencies along the electromagnetic spectrum. Again Stanford technology would solve these challenges.

Now Stanford’s Electronics Research Laboratory delivered another tube which forever changed electronic intelligence receivers – the Traveling Wave Tube (TWT.) Invented in Britain and further developed at Bell Labs, this tube would deliver the “holy grail” for ELINT receivers – instantaneous scan speed and extremely broad frequency range. A Traveling Wave Tube (TWT) could electronically tune through microwave frequencies at 1000 times faster than any other device, and it could operate in a frequency range measured in gigahertz. As a microwave preamp, it had high gain, low noise and extremely wide bandwidth. It was perfect for a new generation of ELINT receivers to be built into the Ferret planes searching for signals around the Soviet Union. Later on TWTs would be built that could not only be used in receivers, but also actually transmit broadband microwaves at high power.

Invention Versus CommercializationWhile Stanford was doing its share of pure research, what’s interesting about the Electronics Research Laboratory (ERL) was its emphasis on delivery of useful products for its customers – the military – from inside a research university. The military had specific intelligence requirements and that meant that a TWT needed to be rugged enough to withstand being put on airplanes. This military/university collaboration for deliverable products is where the Electronics Research Laboratory (ERL) would excel – and ultimately end up leading to its destruction.

Traveling Wave Tube – Source: Thales Electron Devices

The Rise of “Microwave Valley” – More Stanford Tube StartupsThe Traveling Wave Tube generated another series of startups from Stanford’s Electronics Research Laboratory. R. A. Huggins, a research associate at the Stanford’s Engineering Research Lab, left in 1948 to start Huggins Laboratories in Palo Alto and put the first commercially manufactured traveling wave tube on the market. With a boost from military R&D contracts, Huggins Labs continued to expand, diversifying into backward-wave oscillators, low-noise TWTs, and electrostatic focused tubes. (In the 1970’s Huggins Labs sold to an east coast company, Microwave Associates (which became M/A-COM.)

Stanley Kaisel, a research associate at the Stanford ERL tube laboratory, left to join Litton’s startup. He left Litton in 1959 and started Microwave Electronics Corporation (MEC) to make low power, low noise TWTs. He sold the company to Teledyne in 1965.

Venture Capital, Microwaves and the OSS
Dean Watkinsthe leader of TWT research at Stanford’s Electronic Laboratory, left Stanford in 1957 and co-founded Watkins-Johnson (with R.H. Johnson the head of Hughes Aircraft microwave tube department) to market advanced TWTs to the military. Unlike the other Stanford tube spinouts which were funded with military contracts, Watkins-Johnson would be one of the first venture capital funded companies in the valley. Its first round of funding came from Tommy Davis (an ex-WWII OSS agent) then at the Kern County Land Company who knew Fred Terman through his military contacts. Terman and Davis negotiated the Watkins-Johnson investment and would sit on the Watkins-Johnson board together.

Frustrated with Kern’s lack of interest in investing in more technology companies, Tommy Davis would go on to found one of Silicon Valley’s first VC firms with Arthur Rock, creating Davis and Rock, founded in 1961. They would be one the first venture firms to organize their firm as a partnership rather than an SBIC or public company. They would also set the standard for the 20% carry for general partners. Tommy Davis would go on to found the Mayfield Fund in 1969.

These Stanford tube spinoffs joined the growing list of other microwave tube manufacturers in the valley including Eitel-McCullough, Varian, Litton Industries and Stewart Industries. Others would soon join them. By the early 1960s, a third of the nation’s TWT business and a substantial share of the klystron and magnetron industry was located in the Santa Clara Valley– and almost all of these companies emerged from one engineering lab at Stanford.